Multivariate analysis applied to the conservation of monuments: Lichens on the Roman aqueduct Anio Vetus in S. Gregorio

This paper presents the results of a study on the lichen vegetation of the Roman aqueduct, Anio Vetus, located in S. Gregorio near Rome. The study is based on 12 surveys. The data obtained have been submitted to numerical classification and ordination. Different lichen communities can be distinguished on the basis of the results. The ecology of each community and the damage caused to the monuments are discussed on the basis of the ecological indices proposed by Wirth. The intensity of solar radiation seems to be the main facotr leading to decay on the Anio Vetus aqueduct.